Add source code for DSA guest chapter.

src/8.guest/2021/4.dsa/hello_triangle_dsa.cpp

@@ -0,0 +1,147 @@
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+#include <iostream>
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height);
+void processInput(GLFWwindow *window);
+
+const char* vertexShaderSource = "#version 330 core\n"
+"layout (location = 0) in vec3 aPos;\n"
+"void main()\n"
+"{\n"
+"   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+"}\0";
+const char* fragmentShaderSource = "#version 330 core\n"
+"out vec4 FragColor;\n"
+"void main()\n"
+"{\n"
+"   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+"}\n\0";
+
+int main()
+{
+    const unsigned int SCR_WIDTH = 800;
+    const unsigned int SCR_HEIGHT = 600;
+
+    glfwInit();
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 5);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+#ifdef __APPLE__
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+#endif
+
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
+    if (window == NULL)
+    {
+        std::cout << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwMakeContextCurrent(window);
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+    {
+        std::cout << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
+
+    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+    glCompileShader(vertexShader);
+    int success;
+    char infoLog[512];
+    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+    if (!success)
+    {
+        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+    glCompileShader(fragmentShader);
+    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+    if (!success)
+    {
+        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    unsigned int shaderProgram = glCreateProgram();
+    glAttachShader(shaderProgram, vertexShader);
+    glAttachShader(shaderProgram, fragmentShader);
+    glLinkProgram(shaderProgram);
+    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+    if (!success) {
+        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
+    }
+    glDeleteShader(vertexShader);
+    glDeleteShader(fragmentShader);
+
+    float vertices[] = {
+         0.5f,  0.5f, 0.0f,
+         0.5f, -0.5f, 0.0f,
+        -0.5f, -0.5f, 0.0f,
+        -0.5f,  0.5f, 0.0f
+    };
+    // Here we create the VBO with DSA.
+    GLuint vbo = 0;
+    // Note how we do not have to call glBindBuffer() after the create call.
+    glCreateBuffers(1, &vbo);
+    glNamedBufferStorage(vbo, sizeof(vertices), vertices, 0x0);
+
+    unsigned int indices[] = {
+        0, 1, 3,
+        1, 2, 3
+    };
+    // Here we create the EBO with DSA while also specifying that the buffer is mutable from the client side.
+    GLuint ebo = 0;
+    glCreateBuffers(1, &ebo);
+    glNamedBufferStorage(ebo, sizeof(indices), nullptr, GL_DYNAMIC_STORAGE_BIT);
+    glNamedBufferSubData(ebo, 0, sizeof(indices), indices);
+
+    // Here we create the VAO with DSA and specify its format.
+    GLuint vao = 0;
+    glCreateVertexArrays(1, &vao);
+
+    // Specifying our vertex layout with the VAO.
+    glEnableVertexArrayAttrib(vao, 0);
+    glVertexArrayAttribFormat(vao, 0, 3, GL_FLOAT, GL_FALSE, 0);
+    glVertexArrayAttribBinding(vao, 0, 0);
+
+    // Binding the VBO and Element Buffer to the VAO.
+    glVertexArrayVertexBuffer(vao, 0, vbo, 0, sizeof(float) * 3);
+    glVertexArrayElementBuffer(vao, ebo);
+
+    while (!glfwWindowShouldClose(window))
+    {
+        processInput(window);
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+        glUseProgram(shaderProgram);
+        glBindVertexArray(vao);
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+    glDeleteVertexArrays(1, &vao);
+    glDeleteBuffers(1, &vbo);
+    glDeleteBuffers(1, &ebo);
+    glDeleteProgram(shaderProgram);
+    glfwTerminate();
+    return 0;
+}
+
+void processInput(GLFWwindow* window)
+{
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, true);
+}
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+    glViewport(0, 0, width, height);
+}